Ventana software support forum

I've had the same problem recently on 1 out of 3 systems. I think it may be an Excel change. Switching from GET XLS to GET DIRECT may help.

How many datasets do you have? You could create a data variable for each, then switch the data used numerically, rather than switching the source name. It's a little inefficient, but it won't matter unless the dataset is large.

Cool. I can't see through the paywall - is this a hybrid, with CLDs in Vensim and the model in Ventity?

I should add that Ventity has detail and data capability, and is currently free for academic use.

Generally, yes. VECTOR LOOKUP is potentially better because it interpolates, so you could have fewer points than there are time steps in the model.

A feedback-based decision rule is still superior.

I don't know what any of this means, but with a corrected expression it works:

There isn't too much yet, due to the lags in adoption and publication, but if you point us to something, we'd be happy to feature it, and perhaps to start a page on the Ventity site.

To clarify, the equation in the model uploaded appears to differ from the one in your initial post. The model has no solution; the original equation might.

We're working on it, but I'm not sure whether it'll be done by end of year. The speedup is more than noticeable if you have a many-core machine. Older workstations with 16 or more cores are now readily available at dirt cheap prices. We'll keep you posted as this evolves.

I think the immediate problem is that you have the initial guess (initial x) set to 0. If the function's first execution is invalid, it can't proceed with a search.

If you set initial x = 1, it runs, but there's no solution to the equation, so it still fails to converge.

You need to specify the subscript dimension:
0<=timevalues[timerange]<=150

Hossein is correct - the sensitivity seed can't be changed programmatically. We should change that. A workaround is to provide several different vsc files with different seeds. Another possibility is to use the vsc file to vary noise seed, and generate the distributions for the target variables insi...

Add NOISE SEED to the model and change it with SETVAL.
https://www.vensim.com/documentation/noise_seed.htm

Correct. Arrays are a Pro/DSS feature only.

PLE is really focused on learning about dynamics - it doesn't do detail complexity and data.

If you email us, we'd be happy to send you an evaluation license for Pro/DSS for testing.

Are you talking about the units or granularity of the data? Generally it's always better to use the finest time scale you can, given the time step of the model.

This is puzzling ... we've never dropped Euler's method, and there haven't been any changes to the sim engine in v8. If you have a model demonstrating the problem, or a screenshot, we'd be very interested to explore the issue.

Vensim will be looking for time formatted as a decimal year.

The .cin file trick also fails.

Note the provision in the docs for SETVAL: If you are using the SETVAL command to set a string variable do not include the surrounding single quotes. For example: SIMULATE>SETVAL|productname:IS:Metronone However, that alone is not sufficient to resolve the problem - it still seems to fail silently.

There's a little advice on speed here: https://metasd.com/2011/01/optimizing-vensim-models/ One item that's not mentioned there is that restricting the savelist helps. We have an experimental version that does parallel multicore execution, which would reduce your simulation time by a factor of the n...

A similar discussion is here:
viewtopic.php?f=2&t=6873

There are two options: 1. Replace the IF THEN ELSE structure with a VECTOR LOOKUP over time (I think the sample model for VECTOR LOOKUP illustrates this). Then you will have an array of time points, like decisionTime : (t1-t10) with gValue[decisionTime] = 3.5, 2.4, 1.9, 4.2 ... You can then specify ...

In a custom graph, change the x-division and y-division settings.

For the graph tool, you can change the global setting on the Scaling tab of the Control Panel.

Presumably you want to remove all but one. :) Without a legend, it's hard to be sure what this is. You need to do one of the following: - unload datasets using the Control Panel's datasets tab - deactivate subscripts using the Subscript Control - edit the custom graph definition using the Control Pa...

Got it - thanks! I'll put in a ticket and we'll investigate.